The FPR2 receptor is a G protein-coupled receptor that is expressed on inflammatory cells such as monocytes and neutrophils, as well as T cells, and has been shown to play a critical role in leukocyte trafficking during inflammation and human pathology. FPR2 is an exceptionally promiscuous receptor that responds to a large array of exogenous and endogenous ligands, including serum amyloid A (SAA), chemokine variant sCKPβ8-1, the neuroprotective peptide human, anti-inflammatory eicosanoid lipoxin A4 (LXA4) and glucocorticoid-modulated protein annexin A1. FPR2 transduces anti-inflammatory effects of LXA4 in many systems, but it also can mediate the pro-inflammatory signaling cascade of peptides such as SAA. The ability of the receptor to mediate two opposite effects is proposed to be a result of different receptor domains used by different agonists (Parmentier, Marc et al., Cytokine & Growth Factor Reviews 17 (2006) 501-519).
Activation of FPR2 by LXA4 or its analogs and by Annexin I protein has been shown to result in anti-inflammatory activity by promoting active resolution of inflammation which involves inhibition of polymorphonuclear neutrophil (PMN) and eosinophil migration and also stimulating monocyte migration, enabling clearance of apoptotic cells from the site of inflammation in a nonphlogistic manner. In addition, FPR2 has been shown to inhibit natural killer (NK) cell cytotoxicity and promote activation of T cells, which further contributes to down-regulation of tissue damaging inflammatory signals. FPR2/LXA4 interaction has been shown to be beneficial in experimental models of ischemia reperfusion, angiogenesis, dermal inflammation, chemotherapy-induced alopecia, ocular inflammation such as endotoxin-induced uveitis, corneal wound healing, re-epithelialization etc. FPR2 thus represents an important novel pro-resolutionary molecular target for the development of new therapeutic agents in diseases with excessive inflammatory responses.